1. Field of the Invention
This invention relates to apparatus for filtering polluted water or other fluids, and more particularly, to apparatus for filtering storm water run-off and the like.
2. Background
Filter apparatus has long been installed in storm water drain holding sumps in metropolitan areas. These filters are installed to separate out oil sludge and large particulate impurities that may occasionally find their way into storm water drains. The filtered oil sludge and impurities are expected to fall down to the bottom of a sump, where they can be periodically removed by a suction pipe inserted through a service opening.
Commonly installed filter apparatus employ simple screen filter arrangements that tend to clog up; leading to repeated maintenance work and possible filter replacement. To counter and alleviate these well known problems, several different vortex flow filter equipments have been developed and are available for installation. These vortex flow filters direct the inlet flow in a manner which greatly reduces the amount of filter clogging over time, and thereby reduces filter maintenance costs.
However, while the currently available vortex filter units represent improvements in current filter design, even further significant filter changes and improvements are requested by municipal agencies responsible for sewer cleaning, hoping to reduce their burgeoning maintenance and replacement costs.
Presently available vortex filter units typically employ cylindrical filter screens, with the inlet flow velocity usually being uncontrolled. In this arrangement, only one side of the cylindrical screen is available for filtering action, thus limiting the filtering capacity for any given sump installation size. For example, in treatment capacity requirements of 100 cfs or, more, which may be needed in some areas, the necessary filter installation becomes very large, and expensive. Furthermore, inlet constrictions for velocity control are often placed in pipes and difficult to access for cleaning; leading to probably expensive maintenance problems.
Thus, there remain several ongoing problem areas that afflict the typical storm drain filter in use today, resulting in much unavoidable repair and replacement costs.
The present invention incorporates a filter apparatus design that solves much of these problems and greatly reduces costs.
The invention is a variable vortex, baffle fluid filter apparatus that is intended particularly for installation in urban storm water drain sumps. The filter apparatus comprises a circular, filter channel that is enclosed on all four sides by filter screens, a cylindrical baffle screen that is attached concentrically below the channel for moving impurities to the sump bottom, and a means for manually adjusting the velocity of the fluid inlet flow. The filter channel is sized in outer diameter to fit horizontally in a holding sump, with an attached peripheral rim screen filling any space between the channel side and the sump wall. Provision is made for fastening the channel to the sump wall immediately below the inlet pipe opening which is angled so that incoming flow impinges tangentially on the top surface of the filter channel, starting a vortex flow. An adjustable position, pivotable vane is provided in front of the inlet opening to adjust inlet flow velocity and further direct vortex flow. This ensures that the vortex strength is sufficient to concentrate impurity particles at the center of the filter channel opening where they can fall to the bottom of the sump for later removal.
Accordingly, it is a prime object of this invention to provide a filter apparatus which includes means for greatly reducing normal filter clogging by incoming impurities.
Another object is to provide a filter apparatus for storm water drains that increases the available filter area by at least fifty percent for a given filter size, thus reducing filter installation size for any required capacity.
An advantage of the present invention over presently available vortex filter units is its lower installation cost for a given treatment capacity.
Further objects and advantages of the invention will be apparent from studying the following portion of the specification, the claims and the attached drawings.